Sprinkler head

Abstract

The present invention is to discharge the fire extinguishing water by accurately opening the valve, using a shape-memory alloy at a predetermined temperature in a fire. When a shape-memory alloy in a first heat sensitive operation part is heated to a predetermined memory restoring temperature, a pilot valve is operated by the restoring force thereof so that a spool valve can be in a state capable of being opened by an actuator. When a second heat sensitive operation part reaches a predetermined water discharge starting temperature higher than the memory restoring temperature, a fusible alloy provided inside is thermally decomposed so that the first heat sensitive operation part maintained in the closed state is released so as to discharge the fire extinguishing water. When the temperature becomes lower than the memory restoring temperature by the fire extinguishment by the water discharge, a restoring spring deforms the shape-memory alloy into the initial shape so as to drive the valve mechanism into the closed state for stopping the water discharge. Accordingly, since the start of the water discharge can be controlled by the water discharge starting temperature having less fluctuation with respect to the memory restoring temperature, the water can be discharged further accurately. Moreover, since the memory restoring temperature needs not be set accurately, the production efficiency of the sprinkler head can be improved to facilitate the mass productivity.

What is claimed is: 
     
       1. A closed type sprinkler head for discharging fire extinguishing water in a fire, comprising a valve mechanism for switching the channel of the fire extinguishing water, connected to a fire extinguishing piping filled with the fire extinguishing water supplied with pressure, wherein a first heat sensitive operation part where a shape-memory alloy and a restoring force member are arranged facing to each other so that the shape-memory alloy is deformed to an initial shape by the restoring force member so as to maintain a valve mechanism at a water discharge stopping position when the temperature of the shape-memory alloy is lower than a predetermined memory restoring temperature, and the valve mechanism can be driven to a water discharging position by the restoring force of the shape-memory alloy to a memorized shape when the temperature of the shape-memory alloy reaches the memory restoring temperature, and   a second heat sensitive operation part where a predetermined water discharge starting temperature higher than the memory restoring temperature is set so that the valve mechanism is maintained in a closed state regardless of the operation state of the first heat sensitive operation part when the temperature is lower than the water discharge starting temperature, and the closure of the valve mechanism is released so as to discharge fire extinguishing water by thermally disassembling itself at least partially when the temperature reaches the water discharge starting temperature are provided.   
     
     
       2. The sprinkler head according to claim 1, wherein the valve mechanism is in a state capable of being driven to the water discharging position, with the shape-memory alloy temperature lower than the memory restoring temperature, the valve mechanism is closed so as to cease the water discharge by the deforming the shape-memory alloy into the initial state by the restoring force member in the first heat sensitive operation part. 
     
     
       3. The sprinkler head according to claim 2, wherein if the shape-memory alloy temperature regains the memory restoring temperature after stopping the water discharge by deforming the shape-memory alloy in the initial shape by the temperature drop by the water discharge in the first heat sensitive operation part, the water is discharged again by driving the valve mechanism to the water discharging position by the restoring force of the shape-memory alloy to the memorized shape. 
     
     
       4. The sprinkler head according to any of claims 1 to 3, wherein the a plurality of shape-memory alloys are provided in the first heat sensitive part, surrounding the second heat sensitive operation part so that the valve mechanism can be driven to the water discharging position when at least one of the plurality of the shape-memory alloys restores the memorized shape, and the valve mechanism is driven into the closed state so as to stop the water discharge when all of the plurality of the shape-memory alloys restore the initial shape. 
     
     
       5. The sprinkler head according to claim 4, comprising a water sprinkling part to be exposed below the sprinkler head when the second heat sensitive operation part is driven, with the plurality of the shape-memory alloys provided above the exposed water sprinkling part exposed below. 
     
     
       6. The sprinkler according to claim 1, wherein the shape-memory alloy has an initial shape of a coil spring contracted in the axial direction and a memorized shape of a coil spring stretched in the axial direction. 
     
     
       7. The sprinkler head according to claim 1, wherein the shape-memory alloy has an initial shape of a plate spring shape with the center bent in an arc-like shape, and a memorized shape of a plate spring shape stretched in the axial direction. 
     
     
       8. The sprinkler head according to claim 1, wherein the valve mechanism comprises a main valve provided switchably in the channel from the inflow opening to the water discharging opening, an actuator for driving the main valve into the closed position by the pilot pressure supply and driving the main valve into the opened position by the pilot pressure discharge, and   a pilot valve for supplying the pilot pressure to the actuator at the valve position determined by the initial shape of the shape-memory alloy so as to close the main valve and discharging the pilot pressure from the actuator at the valve position determined by the shape-memory alloy deformation to the memorized shape so as to open the main valve for the water discharge.   
     
     
       9. The sprinkler head according to claim 8, wherein the actuator comprises a shaft member having a diaphragm piston or a piston slidably by the introduction or discharge of the pilot pressure integrally, with the diaphragm piston or the piston maintained at the closed state by the second heat sensitive operation part in the ordinary state. 
     
     
       10. The sprinkler head according to claim 1, wherein the valve structure comprises a first valve member provided switchably in the channel from the inflow opening to the water discharging opening, maintained at the closed position by the second heat sensitive operation part, to be driven to the opened position by the release at the time of attaining the water discharge starting temperature for the water discharge,   a second valve member provided in the secondary channel of the first valve member for switching the channel,   an actuator for driving the second valve member to the closed state by the pilot pressure introduction from the inflow opening side and driving the second valve member to the opened state by the pilot pressure discharge, and   a pilot valve for introducing the pilot pressure to the actuator at the valve position determined by the initial shape of the shape-memory alloy so as to drive the second valve member in the closed state and discharging the pilot pressure at the valve position determined by the shape-memory alloy deformation into the memorized state for discharging water, and driving the second valve member into the closed state for stopping the water discharge by the re-introduction of the pilot pressure when the shape-memory alloy restores the initial shape after driving the first valve member into the opened position.   
     
     
       11. The sprinkler head according to claim 1, wherein the second heat sensitive operation part comprises a fusible alloy or a glass valve to be disassembled by the heat attaining the water discharge starting temperature so as to be removed from the second heat sensitive operation part.